Subzero: Use cmov to improve lowering for the select instruction.

src/assembler_ia32.cpp

 //===- subzero/src/assembler_ia32.cpp - Assembler for x86-32  -------------===//
 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Modified by the Subzero authors.
 //
 //===----------------------------------------------------------------------===//
 //
 //                        The Subzero Code Generator
@@ skipping 254 matching lines @@
 
 void AssemblerX8632::lea(Type Ty, GPRRegister dst, const Address &src) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   assert(Ty == IceType_i16 || Ty == IceType_i32);
   if (Ty == IceType_i16)
     EmitOperandSizeOverride();
   EmitUint8(0x8D);
   EmitOperand(dst, src);
 }
 
-void AssemblerX8632::cmov(CondX86::BrCond cond, GPRRegister dst,
+void AssemblerX8632::cmov(Type Ty, CondX86::BrCond cond, GPRRegister dst,
                           GPRRegister src) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  if (Ty == IceType_i16)
+    EmitOperandSizeOverride();
+  else
+    assert(Ty == IceType_i32);
   EmitUint8(0x0F);
   EmitUint8(0x40 + cond);
   EmitRegisterOperand(dst, src);
 }
 
+void AssemblerX8632::cmov(Type Ty, CondX86::BrCond cond, GPRRegister dst,
+                          const Address &src) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  if (Ty == IceType_i16)
+    EmitOperandSizeOverride();
+  else
+    assert(Ty == IceType_i32);
+  EmitUint8(0x0F);
+  EmitUint8(0x40 + cond);
+  EmitOperand(dst, src);
+}
+
 void AssemblerX8632::rep_movsb() {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0xF3);
   EmitUint8(0xA4);
 }
 
 void AssemblerX8632::movss(Type Ty, XmmRegister dst, const Address &src) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(isFloat32Asserting32Or64(Ty) ? 0xF3 : 0xF2);
   EmitUint8(0x0F);
@@ skipping 2291 matching lines @@
   assert(shifter == RegX8632::Encoded_Reg_ecx);
   (void)shifter;
   if (Ty == IceType_i16)
     EmitOperandSizeOverride();
   EmitUint8(isByteSizedArithType(Ty) ? 0xD2 : 0xD3);
   EmitOperand(rm, operand);
 }
 
 } // end of namespace X8632
 } // end of namespace Ice